An illicit discharge carries pollutants into the storm water systems and to streams and lakes from these systems without proper treatment. The pollutants in these discharges can cause odors, public health concerns, and harm aquatic life.

An illicit discharge is an illegal discharge, connection, or tie-in to a storm sewer. Storm sewer systems are designed to convey storm water runoff to nearby lakes and streams. These systems generally do not treat runoff before it empties into a receiving water body. By dumping anything other than storm water into a storm drain, an illicit discharge takes place and is illegal.

An illicit discharge carries pollutants into the storm water systems and to streams and lakes from these systems without proper treatment. The pollutants in these discharges can cause odors, public health concerns, and harm aquatic life.